Reusable water storage minimisation

Two-Stage Optimisation Algorithm for Freshwater and Reusable Water Storage Minimisation... 

Fig. 5.3 Algorithm for reusable water storage minimisation (Majozi, 2006)... 

The solution procedure for the problem stated above involves two optimisation stages in which freshwater and reusable water storage capacity are minimised sequentially, as explained in Section 5.4.1 below. 

The optimisation procedure presented in this chapter entails two stages as summarized in Fig. 5.3. In the first stage, a mathematical model for minimisation of freshwater requirement is solved based on maximum potential reusable water storage, gf. For clarity, this model will be referred to as model Ml in this chapter. In the second stage, the minimum freshwater requirement obtained from model Ml is used as an input parameter in another mathematical model for which the objective function is the minimisation of reusable water storage. This model will be referred to as model M2 in this chapter. Since different amounts of reusable water will be stored at various intervals within the time horizon of interest, the minimum reusable water storage capacity will correspond to the maximum amount of reusable water stored at any point within the time horizon of interest as obtained from model M2 (Constraints (5.40)). 

Gouws, J.F., Majozi, T., Gadalla, M., 2008. Flexible mass transfer model for water minimization in batch plants. Chem. Eng. Process., 47 2323-2335 Gouws, J.F., Majozi, T., 2009. Usage of inherent storage for minimisation of wastewater in multipurpose batch plants. Chem. Eng. Sci., 64 3545-3554 Majozi, T., 2005. Wastewater minimization using central reusable storage in batch plants. Comput. Chem. Eng., 29 1631-1646... 

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